Mujahid (may Allah have mercy on him) says: I was with Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) when a man came to him and said that he had given his wife three divorces. The narrator says: Ibn Abbas (may Allah be pleased with them both) remained silent, until we thought that he would return his wife to him. Then he said: One of you does a foolish thing and then says: O Ibn Abbas! O Ibn Abbas! Allah, the Lord of Might, says: "And whoever fears Allah, He will make for him a way out." [Surah al-Talaq: 2] You did not fear Allah, so I do not find a way out for you. You have disobeyed Allah, and your wife has become separated from you. Allah says: "O Prophet, when you divorce women, divorce them at the start of their waiting period." [Surah al-Talaq: 1] In this narration it is (stated as) three in this way.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الخلع والطلاق / 14943